Chickenpox results from primary infection with varicella zoster virus (VZV) and is characterized by a generalized pruritic vesicular rash, fever, and mild systemic symptoms. Fifteen days after exposure and following a prodrome of fever, malaise, pharyngitis, and/or loss of appetite, the characteristic generalized pruritic vesicular rash develops. The lesions usually develop 24 hours after the onset of illness, appear in crops, start on the trunk and spread peripherally, and evolve from erythematous, pruritic macules to papules and vesicles (rarely bullae) that finally crust over within 48 hours. The classic lesions are teardrop vesicles surrounded by an erythematous ring (“dewdrop on a rose petal”). The most common complication of varicella is secondary bacterial skin infection, usually with S pyogenes or S aureus. Other complications from varicella include encephalitis, glomerulonephritis, hepatitis, pneumonia, arthritis, and meningitis. Cerebellitis (manifested clinically as ataxia) may develop and is usually self-limited. Other viral infections that may manifest with vesicular rashes include herpes simplex, zoster, coxsackie, influenza, echovirus, and vaccinia. On occasion, varicella can be confused with papular urticaria.
Management and Disposition
Suspected varicella infection should lead to strict isolation in a negative air flow room early in the emergency department or office encounter. Most children have a self-limited illness and do not develop any complications. Treatment should be supportive and directed to pruritus and fever control while avoiding salicylates because of their association with Reye syndrome. Oral acyclovir initiated within 24 hours of the onset of the rash may result in a modest decrease in the duration of symptoms and in the number and duration of skin lesions. Acyclovir is not recommended routinely for treatment of uncomplicated varicella in an otherwise healthy child less than 12 years of age. In the immunocompromised host, varicella zoster immunoglobulin (VZIG), IV acyclovir, and hospital admission are indicated.
Varicella (Chickenpox). Multiple cloudy vesicles of varicella. (Photo contributors: Katharine Hanlon and Kara Shah, MD.)
Skin lesions in varicella present in successive crops so that macules, papules, vesicles, and crusted lesions may all be present at the same time.
Healthy children are no longer contagious when all lesions have crusted over (usually 4-5 days from the development of the initial lesions).
Consider oral acyclovir for those at risk for more severe infection, including anyone older than 12 years, with chronic diseases, and taking chronic aspirin or corticosteroid therapy.
PEP should be offered in people who do not have evidence of immunity. PEP includes VZIG within 10 days of exposure in high-risk patients (immunocompromised patients, newborns whose mothers have varicella 5 days before to 2 days after delivery, or pregnant women) or immunization with varicella vaccine within 3 to 5 days of exposure in non–high-risk patients.
Varicella (Chickenpox). Vesicles in different stages of maturation. Note vesicles surrounded ...